Procedure for the optical acquisition of objects by means of a light raster microscope with line by line scanning

ABSTRACT

Procedure for the image acquisition of objects by means of a light raster microscope with line by line scanning, whereas a scanning of the specimen for the creation of a specimen image occurs in scanning steps and the distance between at least two scanning steps is variably adjustable and at least a second scanning of the specimen occurs, during which the position of the scanning steps is shifted with regard to the scanning direction, whereas preferably a line by line scanning of the specimen is carried out.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. Ser. No.10/967,326 filed Oct. 19, 2004.

This application is related to U.S. patent application Ser. No.11/716,678 filed Mar. 12, 2007.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a first embodiment of a laser scanningmicroscope in accordance with the present invention.

FIG. 2 is a diagram showing how a region of interest ROI can be selectedwithin the available maximum scan field using a zoom optic.

FIG. 3 is a schematic view of a second embodiment of a laser scanningmicroscope in which a Nipkow disc is used.

FIG. 4 is a schematic view of a third embodiment of a laser scanningmicroscope in which a multipoint scan is used.

FIG. 5 a shows a scan field of a line scanner having parallel scan linesoffset from each other.

FIG. 5 b shows a scan field in which the scan lines are verticallyshifted by a/2 or a/N, N=2, 3.

FIG. 6 is a schematic illustration of a slider to adjust the proportionof the spatial and temporal resolution of the microscope and select thespeed of the object to be examined.

FIG. 7 a illustrates a monitor image with high optical resolution.

FIG. 7 b illustrates a monitor image in which the optical resolution hasbeen lowered according to the invention (lower image rate).

FIG. 8 illustrations the creation of images with a reduced image rate.

FIG. 9 shows the connection between the detector resolution and thenumber of shifts n.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention is explained in detail in the following with reference tothe drawings.

FIG. 1 shows a scheme of a laser scanning microscope 1, which basicallyconsists of five components: a radiation source model 2, which producesthe stimulating radiation for the laser scanning microscopy, a scanmodule 3, which conditions the stimulating radiation and diffracts overa specimen for scanning, a simplified scheme of microscope module 4directing the scanning radiation, which is produced by the scan module,in a microscopic optical path towards a specimen, as well as detectormodule 5, which receives and detects optical radiation from thespecimen. As may be seen in FIG. 1, the detector module 5 may bedesigned with several spectral channels.

As a general description of a laser scanning microscope with point-wisescanning, it is referred to DE 19702753A1, which thus forms part of thedescription at hand.

The radiation source module 2 produces light radiation, which issuitable for laser scanning microscopy, i.e. particularly radiationwhich may trigger fluorescence. Depending on the application, theradiation source module shows several radiation sources. In arepresented construction, two lasers 6 and 7 are provided in a radiationsource model 2 with a subsequent light valve 8 and an attenuator 9 whichcouple their radiation by means of a coupling 10 into an optical fiber11. The light valve 8 functions as a baffle, by which a beamdeactivation may be achieved without having to deactivate the operationof the laser in laser unit 6 or 7. The light valve 8 may for example bedesigned as AOTF which deviates the laser beam for beam deactivationbefore coupling into the optical fiber 11 towards a light trap, which isnot represented here.

In the exemplary representation of FIG. 1, laser unit 6 shows threelasers B, C, D, whereas laser unit 7 only includes laser A. Therepresentation thus serves as an example for a combined single and multiwave length laser, coupled to one or several fibers. The coupling mayalso occur via several fibers at the same time, the radiation of whichis mixed by a color merger after passing through adaptation optics. Itis thus possible to use various wave lengths or ranges for thestimulating radiation.

The radiation coupled in optical fiber 11 is combined through flexiblecollimate optics 12 and 13 via beam combination mirrors 14, 15 andchanged in a beam forming unit regarding the beam profile.

The collimators 12, 13 ensure that the radiation provided to scan module3 by radiation source module 2 is collimated in an indefinite opticalpath. This preferably occurs with a single objective which by movingalong the optical axis and controlling a (not represented) centralcontrol unit has a focus function, so that the distance betweencollimator 12, 13 and the corresponding end of the optical fiber may bemodified.

The beam forming unit, which will be explained later in detail, formsfrom the rotation symmetric Gauss shaped profiled laser beam, as itoccurs after the ray merging mirrors 14, 15, a linear beam which is nolonger rotation symmetric, but rather creates a rectangular illuminatedfield in profile.

This light beam, which is also described as linear, serves as astimulating radiation and is led via primary color separator 17 and azoom objective, which is yet to be described, to a scanner 18. Theprimary color separator is described later, at this point it shallsimply be said that it separates the specimen radiation, which returnsfrom the microscope module 4, from the stimulating radiation.

The scanner 18 deviates the linear beam uniaxially or biaxially, afterwhich it is bundled by a scan lens 19 as well as by a tube lens and alens of the microscope module 4 into a focus 22, which is located in acompound or specimen. The optical image is created in a way that thespecimen is illuminated in a caustic line with stimulating radiation.

This fluorescent radiation stimulated in the linear focus travels viaobjective and tube lens of the microscope module 4 and the scan lens 19back to the scanner 18, so that in the opposite direction an inactivebeam results from the scanner 18. Therefore, we also say that thescanner 18 de-scans the fluorescent radiation.

The primary color separator 17 lets the fluorescent radiation pass,which is located in wave length areas other than the stimulatingradiation, so that it may be deviated via a deviation mirror 24 in thedetector module 5 and then analyzed. The detector module 5 shows severalspectral channels in the layout of FIG. 1, i.e. the fluorescentradiation coming from the deviation mirror 24 is divided into twospectral channels in an auxiliary color separator 25.

Each spectral channel features a slotted diaphragm 26, which realizes aconfocal or partially confocal image in reference to specimen 23 and thesize of which determines the depth of focus with which the fluorescentradiation may be detected. The geometry of the slotted diaphragm 26 thusdetermines the sectional plane within the (thick) preparation, fromwhich the fluorescent radiation is detected.

The slotted diaphragm 26 is followed by a block filter 27 blockingunwanted stimulating radiation which entered the detector module 5. Thelinearly expanded radiation, which is separated in this way, is thenanalyzed by an appropriate detector 28. The second spectral detectionchannel is designed analogously to the described color channel; it alsocontains a slotted diaphragm 26 a, a block filter 27 a as well as adetector 28 a.

The use of a confocal slotted diaphragm in detector module 5 is only anexample. Of course, a single point scanner may also be used. The slotteddiaphragms 26, 26 a, are then replaced by perforated diaphragms and thebeam forming unit may then be eliminated. Otherwise, all optics aredesigned rotation symmetric for this model. Instead of a point-wisescanning and detection, any multi-point configuration such as pointclouds or the Nipkow disc concept may be used, as explained lateraccording to FIGS. 3 and 4. However, it is then important that thedetector 28 achieves local resolution, since a parallel acquisition ofseveral specimen points occurs during the scanner's sweep.

FIG. 1 shows that the Gauss ray beam present according to the mobile orflexible collimates 12 and 13 is united over mirror stairs with a raymerging mirror 14, 16 and is subsequently converted into a ray beam withrectangular ray profile in the model shown with a slotted diaphragm. Inthe model of FIG. 1, the beam forming unit uses a cylinder telescope 37with a subordinated aspherical unit 38 and subsequent cylinder optics39.

The transformation produces a ray which basically illuminates arectangular field in a profile plane, whereas the intensity distributionalong the longitudinal axis of the field is not Gauss-shaped but ratherbox-shaped.

The lighting configuration with the aspheric unit 38 may serve to evenlyfill a pupil between a tube lens and an objective. In this way, theoptical resolution of the objective may be fully utilized. This optionis therefore also appropriate in a single point or multi point scanningmicroscope system, e.g. in a line scanning system (in the latteradditionally to the axis in which the specimen is focused).

The linear conditioned stimulating radiation is directed towards theprimary color separator 17. It is finished in a preferred design with aspectrally neutral separator mirror according to DE 10257237 A1, thecontent of which is fully included herein. The term “color separator”thus also includes non-spectral separating systems. Instead of thedescribed spectrally independent color separator, a homogenous neutralseparator (e.g. 50/50, 70/30, 80/20 or similar.) or a dichroic separatormay also be used. To allow a selection according to the application, themain color separator is preferably equipped with a mechanism allowing asimple switch, for example by means of a corresponding separator wheelcontaining individual exchangeable separators.

A dichroic primary color separator is particularly suitable to detectcoherent or directed radiation, such as reflection, Stokes' oranti-Stokes' Raman spectroscopy, coherent Raman processes of higherorder, generally parametric non-linear optical processes, such as SecondHarmonic Generation, Third Harmonic Generation, Sum FrequencyGeneration, dual and multi photon absorption or fluorescence. Several ofthese procedures of the non-linear optical spectroscopy require the useof two or several laser beams which are collinearly superimposed.Herein, the represented merging of several laser rays is particularlybeneficial. Basically, the dichroic ray separators common influorescence microscopy may be used. It is also beneficial for Ramanmicroscopy to use holographic notch separators or filters prior to thedetectors in order to suppress the Rayleigh distribution fraction.

In the construction of FIG. 1, the stimulating radiation or lightradiation is fed to scanner 18 via motor controlled zoom optics 41.Therewith, the zoom factor may be adjusted and the scanned visual fieldis continuously variable in a certain regulating range. Particularlybeneficial is a zoom optic where during the adjustment of the focalposition and the image scale, the pupil position is maintained in thecontinuous variable procedure. The three motor degrees of freedom ofzoom optic 41, symbolized in FIG. 1 with arrows, exactly correspond tothe number of degrees of freedom provided for the adjustment of thethree parameters, image scale, focal and pupil position. Particularlypreferable is a zoom optic 41 equipped with a fixed diaphragm 42 on itsdeparture side. In a practical simple realization, the diaphragm 42 mayalso be predetermined by the limitation of the mirror surface of scanner18. The diaphragm 42 on the departure side with zoom optic 41 achievesthat, regardless of the adjustment of the zoom enlargement, a fixedpupil diameter is always projected onto the scan lens 19. The objectivepupil thus remains fully illuminated in any position of zoom optic 41.The use of an independent diaphragm 42 prevents the occurrence of anyunwanted scatter in the area of scanner 18.

Zoom optic 41 cooperates with cylinder telescope 37, which may also bemotor activated and is located in front of the aspheric unit 38. Thisoption has been chosen in the construction of FIG. 2 to create a compactdesign; however, it is not mandatory.

If a zoom factor smaller than 1.0 is required, the cylinder telescope 37is automatically pivoted into the optical path. It prevents anincomplete illumination of the diaphragm 42, when the zoom lens 41 isreduced. The pivoted cylinder telescope 37 thus guarantees that even inzoom factors smaller than 1, i.e. regardless of the adjustment of zoomoptic 41, an illumination line of constant length is always present atthe location of the objective pupil. Compared to a zoom with a simplevisual field, laser performance losses in the light beam may thus beavoided.

Since in the pivoting of the cylinder telescope 37 an image brightnessshift in the illumination line is inevitable, the (not represented)control unit is designed in a way that the advance speed of scanner 18or an amplification factor of detectors in detector module 5 iscorrespondingly adjusted in the activated cylinder telescope 37, inorder to keep the image brightness steady.

Apart from the motor driven zoom optic 41 as well as the motor activatedcylinder telescope 37, remote controlled adjusting elements are alsoincluded in the detector module 5 of the laser scanning microscope ofFIG. 1. In order to compensate longitudinal color errors, for example infront of the slotted diaphragm, a panorama optic 44 as well as acylinder optic 39 and immediately in front of the detector 28, acylinder optic 39 is included, which may be motor relocated along theaxis.

In addition to the compensation of errors, a correction unit 40 isincluded, which will be briefly described below.

Together with the preceding panorama optic 44, the diaphragm 26 as wellas the preceding first cylinder optic 39 and the following secondcylinder optic form a pinhole object of detector configuration 5,whereas the pinhole is realized here by the slotted diaphragm 26. Inorder to prevent unwanted detection of any stimulating radiationreflecting in the system, the cylinder lens 39 is preceded by a blockfilter 27, which shows appropriate spectral characteristics and allowsonly the desired fluorescent radiation to reach the detector 28, 28 a.

A modification of the color separator 25 or the block filter 27inevitably leads to a certain tilt or wedge error at the time ofpivoting. The color separator may lead to an error between the test areaand the slotted diaphragm 26, the block filter 27 to an error betweenslotted diaphragm 26 and detector 28. In order to prevent that areadjustment of the position of the slotted diaphragm 26 or the detector28 is required, a plane-parallel disc 40 is located between the panoramaoptic 44 and the slotted diaphragm 26, i.e. in the optical path of theimage or the detector 28, which may be brought into different tiltingpositions with a controller. The plane-parallel plate 40 is thereforeinstalled in an appropriate adjustable holder.

FIG. 2 shows how with the help of the zoom optic 41 a region of interestROI may be selected within the available maximum scan field SF. If thedrive of the scanner 18 remains so that the amplitude does not change,as this may be required in resonance scanners, an enlargement of morethan 1.0 adjusted on the zoom optic leads to a restriction of the regionof interest centered around the optical axis of the scan field SF.

Resonance scanners are described for example in Pawley, Handbook ofBiological Confocal Microscopy, Plenum Press 1994, page 461ff.

If the scanner is controlled in such a way that it scans asymmetricallyto the optical axis or to the idle position of the scanner mirror, anoffset of the region of interest ROI is achieved in connection with azoom effect. Through the already indicated descanning effect of thescanner 18 and by running the zoom optic 41 again, the selection of theregion of interest ROI in the optical path of detection is eliminatedagain towards the detector. Any selection within the scan field SF maythus be made for the region of interest ROI. In addition, images may bereceived for different selections of the region of interest ROI and maythen compose those to a high-resolution image.

If the region of interest ROI shall not only be shifted with an offsetin reference to the optical axis but at the same time also rotated, aconstruction is appropriate which provides an Abbe-Koenig prism in apupil of the optical path between primary color separator 17 andspecimen 23, which as is known leads to an image field rotation. This isalso eliminated towards the detector. Now images with various offsetsand angles of rotation may be measured and then combined to ahigh-resolution image, e.g. according to an algorithm, as described in apublication by Gustafsson, M., “Doubling the lateral resolution ofwide-field fluorescence microscopy using structured illumination,” in“Three-dimensional and multidimensional microscopy: Image acquisitionprocessing VII,” Proceedings of SPIE, Vol. 3919 (2000), p 141-150.

FIG. 3 shows a further possible construction for a laser scanningmicroscope 1, where a Nipkow disc approach is realized. The light sourcemodule 2, which is represented in a very simplified version in FIG. 3,illuminates a Nipkow disc 64 via mini lens array 65 through the primarycolor separator 17, as described in U.S. Pat. No. 6,028,306, WO 88 07695or DE 2360197 A1 for example. The pinholes in the Nipkow disk, which areilluminated through the mini lens array, are projected onto the specimenin microscope module 4. In order to be able to vary the image size ofthe specimen here as well, a zoom optic 41 is provided.

In modification of the construction in FIG. 1, in the Nipkow scanner theillumination occurs through the opening of the primary color separator17 and the radiation, which shall be detected, is reflected. Inaddition, in modification of FIG. 2, the detector 28 is now designed toachieve local resolution, so that the multipoint illumination achievedwith Nipkow disk 64 is also accordingly scanned in parallel.Furthermore, an appropriate fixed optic 63 with positive refractivepower is arranged between the Nipkow disc 64 and zoom optic 41, whichconverts the radiation coming through the pinholes in the Nipkow disc 64into appropriate bundle diameters. In the Nipkow construction of FIG. 3,the primary color separator 17 is a classic dichroic beam separator,i.e. not the previously mentioned beam separator with a slotted ordotted reflecting area.

The zoom optic 41 corresponds to the previously explained construction,whereas scanner 18 naturally becomes superfluous due to the Nipkow disc64. It can still be included if the selection of a region of interestaccording to FIG. 2 shall be made. The same applies for the Abbe-Koenigprism.

An alternative approach with multipoint scan is shown as a scheme inFIG. 4, where several light sources irradiate at an angle into thescanner pupil. Here too, the use of zoom optic 41 for the projectionbetween primary color separator 17 and scanner 18 allows the realizationof a zoom function as represented in FIG. 2. Through the simultaneousirradiation of light bundles under different angles in a planeconjugated to the pupil, light points in a plane conjugated to theobject plane are created which are directed over a partial area of theentire object plane by scanner 18. The image information results fromthe evaluation of all partial images on a matrix detector 28 with localresolution.

Another version is a multipoint scan, as described in U.S. Pat. No.6,028,306, which is fully included here in this regard. Here too, adetector 28 with local resolution is to be provided. The specimen isthen illuminated through a multipoint light source which is realizedthrough an irradiation expander with subsequent micro lens array, whichilluminates a multi diaphragm plate in a way that a multi point lightsource is realized hereby.

FIG. 5 a shows a scan field of a line scanner with parallel scan linesSL, which offset from each other.

Correspondingly, these scan lines may also be created throughline-by-line punctual scanning with a point scanner.

Offset a is larger here than the distance between the scanned lines at ascan rate which would lead to a maximally possible optical resolution ofthe microscope configuration. However, an object field may be scannedmore rapidly, because the retention period per recorded line for theimage recording determines the speed of the complete recording.

In FIG. 5 b, the scan lines are vertically shifted by a/2 or a/N, N=2,3, the image recording of the individual lines occurs at distance a, butin the spaces between the scanned lines of the scan procedure accordingto FIG. 1 a.

FIG. 6 shows a scheme of a slider to adjust the proportion of thespatial and temporal resolution of the microscope and select the speedof the object which shall be examined.

The scan lines are shifted with the same scan rate at a certain interval(parallel offset of scanner is changed), but here not due to thebleaching effect but rather in order to achieve a compromise inrecording rapid processes or movements with a high demand interval andsimultaneous existence of quasi-static or slowly moving regions orformations in the specimen (almost no movement), where a low demandinterval is required for the image.

For example the scan field of 12 mm with 1024 possible lines is dividedinto 4 times 256 lines utilizing the optical resolution and is scannedfour times shifted by one line.

The scanning of 256 lines thus occurs very rapidly. If the integrationtime for one line is approx. 20 microseconds, the recording of an imageoccurs in 256×20 microseconds, i.e. in about 5 milliseconds.

In the next scan (phase-delayed, next 256 lines), the resolution for theimmobile object will be doubled, while rapidly moving objects appear outof focus. Scan undercuts are carried out until the limit of the opticalresolution is reached. According to the Nysquist criteria, this limit isreached, when the sampling increments correspond to half of the opticalresolution of the microscope. If for example to reach the Nysquistcriteria 2048 lines must be scanned, the demand interval at which thestructures with high spatial resolution may be examined, is 2048×20microseconds, i.e. 40 milliseconds.

Rapidly moving objects initially appear out of focus (due to the lowerspatial sampling resolution), once they remain in one place during theprocess they appear more clearly due to the repeated and offsetscanning.

By recording with lower resolution and at a higher speed (as an overviewscan), rapid movements become visible, which would not be visible inrecordings with the highest resolution (due to the duration of the imagerecording).

With the appropriate input instrument, for example a slider (FIG. 6),the relationship between the temporal resolution At (frame rate) of therecordable velocity V (as expected by the user), with which the objectsmove through the scan field, and the special resolution Ar, is adjusted.This always represents a compromise, which may be optimized by the useraccording to his expectations.

Rapidly moving objects measuring 100 micrometers may be present; in thiscase, a resolution of 1 micrometer is not necessary, the user couldenter a resolution of 10 micrometers and use the increase of therecording speed to improve the acquisition of the object movements.

Objects which are static in comparison to the image rate of themicroscope are represented with optical resolution at the diffractionlimit.

Dynamic objects moving faster than the image rate are represented with aspatial resolution of the sampling rate, which is generally lower thanthe optical resolution.

When recording a time series, dynamic objects initially appear out offocus, but as soon as they become static, they are represented with theresolution at the diffraction limit.

Rapid dynamic objects may become visible by correlation of individualimages to each other. This is done by coloring correlated points (of theimages recorded successively) with one color and the remaining pointswith a different color.

A color coded overlay of fast and slow moving objects may occur, whereasthe static image information may be separated by a correlation of theimages. The image points correlating at different times are used forthis purpose.

In FIG. 7 a, a monitor image with high optical resolution isrepresented.

On the right, in an enlarged section of the left figure part, rapidlymoving objects are represented, which are only visible in one locationdue to the high optical resolution.

In FIG. 7 b, the optical resolution has been lowered according to theinvention (lower image rate).

Hereby, faster moving objects (represented in exaggeration) appear outof focus, whereas static objects continue to appear clearly. Themovements of the unclear objects may be observed and recorded.

The creation of images with a reduced image rate is explained in FIG. 8.

Line detector is located on x-axis, shifting on y-axis, signals used forthe formula (Ck,i) j shift increment is vertical (in y-direction).

The measured signals in individual channels are marked with (ckij)j,whereas i=1 . . . N is the channel number of the line detector, k is thenumber of lines and j=0 . . . n−1 is a multiple of the shift a/n. Percolumn, for the calculation of the N times n values Sm, differences ofsums are calculated for individual values according to the followingalgorithm:

$S_{1} = {c_{1,0}^{\prime} = {{\sum\limits_{i = 1}^{N}\; c_{i,0}} - {\sum\limits_{i = 1}^{N - 1}\; c_{i,1}}}}$$S_{2} = {c_{1,1}^{\prime} = {{\sum\limits_{i = 1}^{N}\; c_{i,1}} - {\sum\limits_{i = 1}^{N - 1}\; c_{i,2}}}}$⋯$S_{n - 1} = {c_{1,{n - 2}}^{\prime} = {{\sum\limits_{i = 1}^{N}\; c_{i,{n - 2}}} - {\sum\limits_{i = 1}^{n - 1}\; c_{i,{n - 1}}}}}$$S_{n} = {c_{1,{n - 1}}^{\prime} = {{\sum\limits_{i = 1}^{N - 1}\; c_{i,{n - 1}}} - {\sum\limits_{i = 2}^{N}\; c_{i,0}} - {\sum\limits_{m = 1}^{n - 2}\; c_{N,m}}}}$⋯$S_{{k \cdot n} + 1} = {c_{k,0}^{\prime} = {{\sum\limits_{i = k}^{N}\; c_{i,0}} - {\sum\limits_{i = k}^{N - 1}\; c_{i,1}}}}$$S_{{k \cdot n} + 2} = {c_{k,1}^{\prime} = {{\sum\limits_{i = k}^{N}\; c_{i,1}} - {\sum\limits_{i = k}^{N - 1}\; c_{i,2}}}}$⋯$S_{{k \cdot n} + j + 1} = {c_{k,j}^{\prime} = {{\sum\limits_{i = k}^{N}\; c_{i,j}} - {\sum\limits_{i = k}^{N - 1}\; c_{i,{j + 1}}}}}$⋯$S_{{{({k + 1})} \cdot n} - 1} = {c_{k,{n - 2}}^{\prime} = {{\sum\limits_{i = k}^{N}\; c_{i,{n - 2}}} - {\sum\limits_{i = k}^{N - 1}\; c_{i,{n - 1}}}}}$$S_{{({k + 1})} \cdot n} = {c_{k,{n - 1}}^{\prime} = {{\sum\limits_{i = k}^{N - 1}\; c_{i,{n - 1}}} - {\sum\limits_{i = {k + 1}}^{N - 1}\; c_{i,0}} - {\sum\limits_{m = 1}^{n - 2}\; c_{N,m}}}}$⋯S _(N·n−n) =c _(N,0) ′=c _(N,0)

S _(N−n−n−1) =c _(N,1) ′=c _(N,1)

. . .

S _(N·n) =c _(N,n−1) ′=c _(N,n−1)

The calculated S values (interim values per column) may then begraphically represented on the indicated image, e.g. by means of a scan.

FIG. 9 shows the connection between the detector resolution and thenumber of shifts n based on the configuration described above. For n=1,the spatial resolution of the detection unit equals the spatialresolution of the increment (a). For 5 shifts at a/s, the spatialresolution of the detection unit is a/5. The maximum spatial resolutionwhich may be achieved is determined by an optical limit resolution ofthe microscope. According to the scan theorem by Nyquist, this maximumspatial resolution (□□) is reached exactly when the detector resolutionis equal to half of the potential resolution of the microscope (□□).This corresponds to a number:

$n_{\max} = {2 \cdot \frac{L}{\Delta \; \rho}}$

In the strip projection (7505), partial images are recorded andcalculated and thus a higher resolution is achieved. If these partialimages were utilized to obtain information, they could be used with alower local resolution but a higher temporal resolution (e.g. threetimes faster).

Image information from the recorded partial images could thus beobtained, whereas by interpolation a scan of the image could beequalized, which could at the same time provide information on the rapidmovements in the image. The grid could here be hidden by averaging overa grid period or by evaluating the maximum points.

FIG. 2 shows a further definition of the invention.

If, due to the increased acquisition velocity of specimens with aconfocal microscope, lines or images are skipped, fluorescence specimensshow an irregular bleaching or strong bleaching of certain regions. Withthe procedure described here, a uniform bleaching of the specimen may beachieved.

To increase the recording velocity in the acquisition of images withconfocal microscopes, only every n-th line is illuminated and recorded(FIG. 10). The intensity values for the skipped lines are interpolatedfrom the intensities of neighboring pixels. In time series andcontinuous data acquisition, individual lines in a fluorescence specimenare bleached, while the neighboring regions are not bleached.

A reference acquisition here describes an image acquisition, where themetric distance of the recorded pixels is equal in both imagedirections. The image directions are designated with x- and y direction,whereas the x-direction in punctual illumination of the specimen is thedirection in which the point is rapidly moved during the scan of thespecimen. In an illumination of the specimen line by line, thex-direction shall be the direction of the line. The y-direction shall bepositioned vertically to the x-direction and in the image plane.

A whole-numbered nesting value n is determined, which indicates how manylines are skipped during the accelerated data acquisition iny-direction. During a repeated acquisition of an image, the specimenwill not be scanned in the same spot but rather shifted by a certainamount in y-direction. The amount of shifting may be different for everyline. However, the procedure is simpler, if the same amount is used. Inthe simplest case, the amount of shifting corresponds to the value ofthe line distance in y-direction from the reference image, andilluminated in the n*i-th image acquisition with whole-numbered i in thesame spot as in the first image.

With this procedure, a uniform bleaching of the specimen is achieved.The maximum bleach effect for individual cells may be reducedapproximately by the factor 1/n.

The procedure may be used for the acquisition of images with imageplanes of any orientation relative to the illumination direction. Apartfrom scanners and piezo drives, other drives may be used for theshifting.

For the acquisition of image batches, a procedure may be used which isbased on the same idea and simply represents a generalization on afurther dimension.

During this process, individual images of the batch recorded during thenext acquisition of the batch are shifted vertically to the image plane.The procedures of the nested acquisition of images and batches may alsobe used simultaneously.

The invention is not based on the line by line scanning. In Nipkowscanners, the evaluation of a part of the perforated spirals or otherperforated configurations could be eliminated in an initial step andthen other perforated configurations could be used in a further step.

In multipoint configurations, that are moved over a specimen, certainpoint areas or point lines could be used for evaluation.

The described invention represents a considerable increase ofpossibilities of use of rapid confocal laser scan microscopes. Thesignificance of such a further development may be analyzed according tothe standard literature on cell biology and the rapid cellular andsub-cellular procedures1 described therein as well as the used researchmethods with a number of dyes2.

See:

¹B. Alberts et al. (2002): Molecular Biology of the Cell; GarlandScience.

^(1,2)G. Karp (2002): Cell and Molecular Biology: Concepts andExperiments; Wiley Text Books.

^(1,2)R. Yuste et al. (2000): Imaging neurons—a laboratory Manual; ColdSpring Harbor Laboratory Press, New York.

²R. P. Haugland (2003): Handbook of fluorescent Specimens and researchProducts, 110th Edition; Molecular Specimens Inc. and MolecularSpecimens Europe BV.

The invention is particularly important for the following processes andprocedures:

Development of Organisms

The described invention may be used, among other things, for theanalysis of development processes, which are mainly characterized bydynamic processes from one tenth of a second up to an hourly range.Examples used on the level of united cell structures and whole organismsare described herein among other things:

In 2003, Abdul-Karim, M. A. et al. described in Microvasc. Res.,66:113-125 along term analysis of blood vessel changes in live animals,whereas fluorescence images were recorded in intervals over severaldays. The 3D data acquisitions were evaluated with adaptive algorithms,in order to schematically represent movement trajectories.

In 2003, Soll, D. R. et al. described in Scientific World Journ.3:827-841a software based movement analysis of microscopic data ofnuclei and pseudopodia of live cells in all 3 spatial dimensions.

In 2002, Grossmann, R. et al. described in Glia, 37:229-240 a 3Danalysis of the movements of microglia cells in rats, whereas the datawas recorded over a period of up to 10 hours. At the same time, aftertraumatic damage, fast reaction of the Glia could be observed, so that ahigh data rate and corresponding data volume results.

This particularly concerns the following key points:

Analysis of live cells in a 3D environment, the neighboring cells ofwhich react sensitively to laser and must be protected from theillumination in the 3D-ROI;

Analysis of live cells in a 3D environment with markings which shall bebleached systematically by laser in 3D, e.g., z.B. FRET experiments;

Analysis of live cells in a 3D environment with markings which arebleached systematically by laser and shall be observed at the same timeoutside of the ROI, e.g. FRAP- and FLIP-experiments in 3D;

Systematic analysis of live cells in a 3D environment with markings anddrugs showing manipulation determined changes by laser illumination,e.g. activation of transmitters in 3D;

Systematic analysis of live cells in a 3D environment with markingsshowing manipulation determined color changes by laser illumination,e.g. paGFP, Kaede;

Systematic analysis of live cells in a 3D environment with very weakmarkings, which require an optimal balance of confocality againstdetection sensitivity.

Live cells in a 3D tissue compound with varying multiple markings, e.g.CFP, GFP, YFP, DsRed, HcRed or similar.

Live cells in a 3D tissue compound with markings showing functiondetermined color changes, e.g. Ca+ markers

Live cells in a 3D tissue compound with markings showing developmentdetermined color changes, e.g. transgenic animals with GFP

Systematic analysis of live cells in a 3D environment with markingsshowing manipulation determined color changes by laser illumination,e.g. paGFP, Kaede

Systematic analysis of live cells in a 3D tissue compound with very weakmarkings, which require a restriction of confocality in favor of thedetection sensitivity.

The last named point is combined with the preceding.

Transportation Processes in Cells

The described invention is excellent for the examination ofintracellular transportation processes, since relatively small motilestructures, e.g. proteins, with high speed, must be represented here(mostly in the area of hundredth of seconds). In order to record thedynamics of complex transportation processes, applications such as FRAPwith ROI bleaches are often used. Examples for such studies aredescribed in the following:

In 2000, Umenishi, F. et al. described in Biophys J., 78:1024-1035 ananalysis of the spatial mobility of Aquaporin in GFP transfected culturecells. For this purpose, points in the cell membrane were systematicallyand locally bleached and the diffusion of the fluorescence was analyzedin the environment.

In 2002, Gimpl, G. et al. described in Prog. Brain Res., 139:43-55experiments with ROI bleaches and fluorescence imaging to analyze themobility and distribution of GFP marked Oxytocin receptors infibroblasts. This poses high requirements to the spatial positioning andresolution as well as the direct temporal consequence of bleaching andimaging.

In 2001, Zhang et al. described in Neuron, 31:261-275 live cell imagingof GFP transfected nerve cells, whereas the movement of granuli wasanalyzed by combining bleach and fluorescence imaging. The dynamics ofthe nerve cells places high requirements to the velocity of the imaging.

Interaction of Molecules

The described invention is particularly convenient to representmolecular and other sub-cellular interactions. Herein, very smallstructures with high velocity (in the area of hundredth of seconds) mustbe represented. In order to dissolve the spatial position of themolecules required for the interaction, indirect techniques such as FRETwith ROI bleaches are used.

Used examples are described in the following:

In 2004, Petersen, M. A. and Dailey, M. E. describe in Glia, 46:195-206a dual channel acquisition of live hippocampus cultures in rats, whereastwo channels were recorded spatially in 3D and over a longer period oftime for the markers Lectin and Sytox.

In 2003, Yamamoto, N. et al. described in Clin. Exp. Metastasis,20:633-638 a two color imaging of human fibrosarcoma cells, whereingreen and red fluorescent protein (GFP and RFP) were observedsimultaneously in real time.

In 2003, Bertera, S. et al. described in Biotechniques, 35:718-722 amulticolor imaging of transgenic mice marked with timer reporterprotein, which changes its color from green to red. The imageacquisition occurs as fast series 3-dimensionally inside the tissue of alive animal.

Signal Transfer Between Cells

The described invention is excellent for the examination of extremelyfast signal transfer procedures. These often neurophysiologicalprocesses pose high requirements to the temporal resolution, since theactivities transmitted by ions are in the range of hundredths to lessthan thousandths of seconds. Used examples of studies of the muscle andnerve system are described here:

In 2000, Brum G et al. described in J Physiol. 528: 419-433 thelocalization of rapid Ca+ activities in the muscle cells of a frog afterstimulation with caffeine as a transmitter. The localization andmicrometer precise resolution was only possible due to the use of a fastconfocal microscope.

In 2003, Schmidt H et al. described in J Physiol. 551:13-32 an analysisof Ca+ ions in nerve cell appendages of transgenic mice. The study ofrapid Ca+ transients in mice with altered Ca+ binding proteins couldonly be carried out with the help of high resolution confocalmicroscopy, since a localization of the Ca+ activity within the nervecell and its exact temporal kinetics play an important role.

1. Process for image acquisition of objects using a light rastermicroscope with line by line scanning, comprising the steps of: (a)scanning of a specimen line by line in parallel scan lines in a scanningdirection for the creation of a specimen image, wherein the distancebetween at least two scan lines is variably adjustable, and (b) carryingout at least a second scanning of the specimen, during which theposition of the scan lines is shifted with regard to the scanningdirection.
 2. Process according to claim 1, further comprising the stepof changing the proportion between spatial and temporal resolution ofthe microscope.
 3. Process for studying development processes, using theprocess of claim 1, wherein in step (a), the specimen exhibits dynamicprocesses on the level of united cell structures and whole organismslasting from tenths of seconds up to hours.
 4. Process according toclaim 3, wherein the specimen is living cells in a three-dimensionaltissue group with markers, which exhibit manipulation related changes incolor by laser illumination, in combination with living cells in athree-dimensional tissue group with very weak markers, and wherein theprocess further comprises the step of restricting confocality in favorof detection sensitivity.
 5. Process for studying intracellulartransportation processes, using the process of claim 1, wherein thespecimen is motile structures, with high speed in the area of hundredthof seconds in and wherein the scanning of steps (a) and (b) is carriedout using FRAP with region of interest bleaches.
 6. Process for studyingmolecular and other sub-cellular interactions, using the process ofclaim 1, wherein the specimen is a very small structure with highvelocity, and wherein the scanning of steps (a) and (b) is carried outusing indirect techniques with region of interest bleaches for theresolution of submolecular structures.
 7. Process for studying fastsignal transmitting procedures, using the process of claim 1, whereinthe specimen exhibits neurophysiological processes with high temporalresolution.